The present disclosure generally relates to getter precursors for hermetically sealed packaging.
Hermetically sealed packages for devices such as optoelectronic devices are often designed to protect their contents from the external environment. Most of these devices are made of a layered structure incorporating different layers of materials each having diverse functionalities. One common way to protect these devices includes providing encapsulation to the layered structure. Typically, the procedure to encapsulate the device includes sandwiching the device between a substrate and an encapsulation layer such that there is a continuous perimeter seal around the device. While glass and metal provide excellent protection, they are often lacking in terms of cost, weight, ruggedness, and/or transparency. Plastics offer these latter attributes, but lack hermeticity. Barriers can be added to limit moisture and oxygen ingress; however the addition of scavengers can improve performance. In addition, all substrates (metal, glass, and plastic) are typically assembled using organic-based adhesives, often based on epoxies. These adhesives become pathways for moisture and oxygen ingress. Addition of getters to the package is often disposed within the package to minimize any degradation effects caused by moisture and/or oxygen permeation.
Getter materials incorporated into packages generally fall into 2 categories: already active materials and precursors to active materials. Already active materials include certain reactive metals and their alloys along with molecular compounds. Because of their reactivity to moisture and/or oxygen, these materials must be processed under inert conditions. Precursors to getters can be processed in the air, but require activation prior to incorporation into the package. Since activation of these prior art precursors often results in expulsion of oxygen and/or water, activation cannot occur within the package. Once activated, these materials must be handled under inert conditions.
Exemplary prior art getter materials include metal oxides, alkaline earth metal oxides, sulfates, metal halides, or perchlorates, molecular sieves, alumina, auxite, clays, silica gets, various zeolites, and the like. While these materials are satisfactory for their intended purpose, they do require special handling and processes for incorporation into the package.
Accordingly, there exists a need for improved materials and methods for incorporating getters into the package.